At 7:45 a.m., Dana Yoerger rushed through Alvins hangar,
clutching a piece of paper just out of the color printer. He
handed it to Expedition Leader Pat Hickey, who had kept Alvins
hatch open. Todays diversAnna-Louise Reysenbach,
Dan Scheirer, and Pilot Bruce Strickrottwere already in Alvins titanium
sphere, waiting to dive. Hickey handed the paper down to them,
closed the hatch, and Alvin set off on a final dive in
the seafloor region where the Rose Garden vent field
was last seen in 1990.

The paper marked the location where ABE, the Autonomous Benthic
Explorer, had detected a tiny spike in the temperature of waters
at the ocean bottoma telltale sign of possible hydrothermal
venting. Overnight, ABE had flown across an expanse of seafloor,
at a constant altitude of 40 meters above it. It used its sonar
to make a highly detailed seafloor map, and it sniffed using
a CTD for any signs of warm plumes wafting out of hydrothermal
vents. The rise in water temperature that ABE detected
was ever so slight10 to 20 millidegrees. A millidegree
is one-thousandth of a degree.

The Alvin crew followed the detailed map
made by ABE. It gave them
a feeling for the entire region they were traveling through, and where they
were in it. It was like hiking with a good topographic map, Anna-Louise
said.
We covered a lot of ground, Dan Scheirer said, and Anna-Louise continued, We
saw lava, lava, and more lavapunctuated by lava.

They headed toward the spot where ABE detected
the temperature spike, and following ABEs map, found
it rather easily. Shimmering water seeped out of a small seafloor
crack, perhaps 4m long. It was 11°C (52°F).
That is not very warm, and the site is not very big. But ABE had detected
it.

Its a testament to ABEs sensitivity, Dan Fornari
said. To find something like that on the seafloor is like finding a needle
in a haystack.

You can find a needle with ABE, Anna-Louise
said.

There was no large vent life at this tiny vent,
and it was the only sign of venting Alvin found
today. No Rose Garden. Over the past four days, ABE has mapped
a seafloor area 3 to 4 square kilometers. If ABE is detecting
little temperature spikes like the one today, it gives us confidence
that were not missing
any big ones, Dana said. Every other time people have come here,
they found Rose Garden. This strengthens the case that Rose Garden is gone.

That was a bit of a disappointment for Co-Chief
Scientist Tim Shank. He had dreamed of returning to Rose Garden
to chronicle how the community of animals living around it had
changed since 1990. He had wanted to keep building on the longest-running
history of a vent community. It is impossible to say for certain,
but the evidence is strong that a seafloor volcanic eruption since
1990 may have destroyed the Rose Garden.
Its a strong reminder that these vent sites change all the time, Tim
said. Chemistry creates these habitats and geology can take them away.

Nature taketh away, but it also giveth. On this
voyage, we discovered a new vent sitepossibly a very young onewhich was christened Rosebud. We
have mapped it extensively. And years from now, scientists may return to learn
how the communities at Rosebud have grown up and changedto
see the circle of life on the seafloor.